Electric fuse

Abstract

A cartridge type fuse having a casing. A pair of terminal plugs is press-fitted into the ends of said casing and conductively interconnected by a fusible element. Each of said pair of terminal plugs has a knurled lateral wall. A pair of annular fasteners is mounted on said casing each adjacent one of the ends thereof. Said fasteners press the wall of said casing radially inwardly into firm engagement with said knurled lateral walls of said pair of terminal plugs. The casing preferably includes an outermost ply of woven glass cloth, an innermost ply of woven glass cloth, and at least one intermediate ply of relatively loose non-woven fibers sandwiched between said outermost ply and said innermost ply, and the constituent plies of said casing are preferably integrated by polyester resin.

I claim as my invention: 
     
       1. An electric fuse including (a) a fusible element immersed in a pulverulent arc-quenching filler;   (b) a tubular fuse casing of a relatively elastic and relatively soft reinforced synthetic resin having the same cross-section along the entire length thereof housing said fusible element and said filler;   (c) a pair of circular terminal plugs having end surfaces of substantially equal area press-fitted into the ends of said casing and conductively interconnected by said fusible element, said pair of terminal plugs having knurled lateral walls; and   (d) a pair of annular fasteners exposing the axially outer end surfaces of said pair of terminal plugs mounted on said casing each adjacent one of the ends thereof and pressing the wall of said casing radially inwardly into firm engagement with said knurled lateral walls of said pair of terminal plugs.   
     
     
       2. A fuse as specified in claim 1 wherein said casing comprises an innermost ply of a woven glass cloth, an outermost ply of woven glass cloth, at least one intermediate ply of non-woven glass mat arranged between said innermost ply and said outermost ply and wherein said plies are united by a polyester resin. 
     
     
       3. A fuse as specified in claim 1 wherein said pair of terminal plugs have cross-knurled lateral walls 
     
     
       4. A fuse as specified in claim 1 wherein each of said pair of annular fasteners is formed by a metal ring. 
     
     
       5. A fuse as specified in claim 1 wherein each of said pair of annular fasteners is formed by an aluminum ring. 
     
     
       6. A fuse as specified in claim 1 having a plurality of fusible elements wherein said pair of terminal plugs have grooves for receiving the ends of said plurality of fusible elements, and wherein the knurl of the lateral walls of said pair of plugs stops at a level defined by the bottom of said grooves.